420 Dr. Henry on the Action of [June, 



There is not, however, as with carbonic oxide, any production of 

 carbonic acid ; but in the course of a few minutes the inside of 

 the tube becomes coated with a brownish substance, soluble in 

 water, and communicating to it the same colour ; having a smell 

 resembling that of a burnt animal substance ; and yielding 

 ;immonia on the addition of a drop or two of liquid potash. It 

 was produced in too small a quantity to enable me to submit it to 

 a more minute examination; but its characters appeared to 

 resemble those of a product, obtained by M. Gay-Lussac, by 

 mixing cyanogen with ammoniacal gas.* 



If oxygen be added to a mixture of hydrogen and cyanogen, 

 in quantity sufficient to saturate both the gases, it is still neces- 

 sary, in order that an immediate effect should be produced by 

 the sponge, that the hydrogen should exceed the cyanogen in 

 volume. A decided action then takes place ; an immediate 

 absorption ensues ; fumes of nitrous acid vapour appear, which 

 act on the surface of the mercury ; and, after transferring the 

 gas into a dry tube, carbonic acid is found to have been pro- 

 duced, equivalent in volume to double that of the cyanogen. 



5. Effect of adding various other Gases to an Explosive Mixture 



of Hydrogen and Oxygen. 



It had been already ascertained by Prof. Dobereiner, that one 

 volume of oxygen, diluted with 99 volumes of nitrogen, is still 

 sensible, when mixed with a due proportion of hydrogen, to the 

 action of the sponge.t Carbonic acid, also, even I find when it 

 exceeds the explosive mixture ten times, retards only in a slight 

 degree the energy of the sponge. Oxygen, hydrogen, and nitrous 

 oxide gases, when employed to dilute an explosive mixture, are 

 equally inefficient in preventing the mutual action of its ingre- 

 dients. Ammonia may be added in ten times the volume of the 

 explosive mixture, and muriatic acid gas in six times its volume, 

 with no other effect than that of rendering the action of the 

 sponge less speedy. 



6. Mixtures of Carbonic Oxide and Carburetted Hydrogen toith 



Oxygen. 



When mixtures of these gases are exposed to the sponge, the 

 carburetted hydrogen seems to stand entirely neutral. The 

 carbonic oxide is converted into carbonic acid, in the same 

 gradual manner as if it had been mixed with oxygen only, and 

 the carburetted hydrogen remains unaltered. 



* Annales de Chimie, xcv. 196. 



+ In analysing atmospheric air by adding hydrogen to it, and acting on the mixture 

 by a platinum ball, I have generally obtained a diminution indicating more than 21 per 

 cent, of oxygen. This I find to be owing to the absorption of a small quantity of nitro- 

 gen by the ball, especially when, after being heated, it has been rapidly passed hot 

 through the mercury. 



